Time-varying Formation Tracking Control For Networked Multi-agent Systems

Motion coordination is an important application area of multi-agent systems.In engineering applications,the desired relationships among agents in formations are widely time-varying even non-linear.However,there are few results on general time-varying formation control for multi-agent systems.Therefore,the main objective of this paper is to propose a solution on time-varying formation for multi-agent systems with reference input.On the control of multi-agent systems,networked communication constraint is a considerable factor,which affects the control performance of systems greatly,even influences the stability of systems.Statistic-based strategies and model-based compensation strategies are two typical widely used solutions.Generally,statistic-based strategies rely on networked characteristics that follows specified probability distribution,thus,the engineering application is limited.The Networked Predictive Control(NPC)is a useful engineering method for networked communication constraint compensation.However,in existing literatures,the implementation of NPC on multi-agent systems are in a passive compensation form,which relies on repetitive implementations of dynamic compensators for the networked delay.Hence,the computation efficiency of the whole system is sacrificed for networked delay compensation.To solve the time-varying formation control for networked multi-agent systems with reference input.The concept of consensus for multi-agent systems is extended to timevarying consensus,and the design of time-varying consensus protocol and analysis on stability for both first-order planar networked multi-agent systems and general linear networked multi-agent systems are presented.Moreover,to achieve general time-varying formations,the F-consensus for multi-agent systems is presented.On the solution of inter-agent communication constraint,an active predictive compensation mechanism is presented,which solves the low computational efficiency of passive compensation strategies.To verify the engineering effectiveness of proposed control strategies,a networked controller Netcontroller-DM3730 is designed and implemented,on the basis of which a novel Networked Control Systems simulation and experiment platform is implemented.Moreover,the tracking control strategies for wheeled mobile robots with delay and dataloss in the feedback channels is presented to improve the robustness of experimental platforms on delay and data-loss of localization systems.On the basis of proposed theory results and engineering verification platforms,various experiments and real-time simulations with both local and worldwide networked environment are presented.Results of experiments and real-time simulations shows that the proposed strategies are effective on time-varying formation tracking problems for networked multi-agent systems.So far as we known,the surrounding formation of Wheel Mobile Robots(WMRs),formation of multi-robots with fixed distance on a desired curve path are both implemented for the first time in this paper.